In recent years, for example, semiconductor integrated circuits (large scale integration (LSI), target circuits, chips) have utilized a technique called Adaptive Supply Voltage (ASV) to reduce power consumption.
The ASV technique is to reduce power consumption by, for example, controlling a power supply voltage to be lowered regarding chips of which processes vary on Fast side (a current flowing side) according to the variation.
As a method for obtaining an effect of the ASV more actively, an ASV technique according to temperature has been suggested. The ASV technique according to temperature is to realize further reduction of power consumption by, for example, installing a temperature sensor within an LSI and controlling a voltage based on a temperature detected by the temperature sensor.
As described above, for example, the ASV technique has been adopted to reduce power consumption of semiconductor integrated circuits. However, the above-described ASV technique only associates an operable voltage with a monitor value and a temperature of processes.
Thus, for example, a table for controlling voltage is expected to guarantee operation with respect to any LSIs, and it becomes difficult to control the individual LSIs at an optimum voltage.
In other words, the above-described ASV technique is not for controlling each individual LSI to the respective optimum voltage, and it may be thought that there is a room for further improvement in reduction of power consumption. Further, in order to adopt the above-described ASV technique, for example, components such as a temperature sensor will be installed, and thus there are issues in cost, occupancy area, and usability.
Conventionally, various suggestions have been made to reduce power consumption of semiconductor integrated circuits by adopting the ASV technique.
Patent Document 1: Japanese Laid-open Patent Publication No. 2011-227937
Patent Document 2: Japanese Laid-open Patent Publication No. 2000-214221